1. Field of the Inventions
The present inventions relate generally to small watercraft with a device for inhibiting water from entering an engine, and more particularly to a small watercraft that has a device for inhibiting water from entering its engine when the watercraft overturns.
2. Description of Related Art
Relatively small watercraft such as, for example, personal watercraft have become popular in recent years. This type of watercraft is quite sporting in nature and carries one or more riders. An internal combustion engine typically powers a jet pump unit that propels the watercraft by discharging a stream of water rearwardly. A hull of the watercraft forms an engine compartment and a tunnel in the rear-most and underside of the watercraft. The engine lies within the engine compartment. The jet pump unit generally is placed within the tunnel and includes an impeller driven by the engine to discharge the water. Occasionally, such a watercraft will overturn.
The watercraft use one or more air ducts to supply air to a generally enclosed engine compartment. The air is drawn from within the engine compartment for combustion. Thus, when such a watercraft overturns, water can enter the engine compartment and the engine itself through an air intake system of the engine, which can disable or damage the engine.
To reduce the likelihood of such engine damage, an shut-off system has been used. The shut-off system can have an overturn sensor or switch. The overturn switch generally detects watercraft movement that is consistent with a watercraft that is overturning. When such movement is detected, the overturn switch outputs a signal that is used to shut-off the engine or to stop an operation of the engine. By stopping the engine operation, induction of water into the engine is much less likely during watercraft inversion.
Typical overturn switch designs generally are gravity-biased or centrifugal in nature. When the associated watercraft overturns, the switch's position relative to gravity may cause the switch to detect the overturn or the rapid movement of the switch may cause the switch to detect the overturn. However, some watercraft are designed for sporting operation and often are operated in manners that cause rapid directional changes, for example, during operation over rough water. Such activities can cause the typical overturn switches to falsely indicate an overturn leading to an undesirable and unnecessary engine stop.
Some watercraft control systems allow the engine to continue to operate for a preset period of time after the overturn switch has generated the signal. For example, U.S. Pat. No. 6,648,702 discloses such a watercraft.